You go with the anal option that your friend tells you about. As you would be facing away from him so you wouldn't have to see it. Your friend stands up and says, " okay, undress yourself... this can get messy." You undress yourself... nervous as this is the first time anybody outside your parents have seen you naked. You see before turning the other way your friend unzipping his pants. " Operation gender-flow type 2 nano-bots...initaite program." Your friend says in a almost mechanical voice.
You wait, for a few seconds before feeling something dig into your butt. You realize that it's your friend's dick...somehow extending itself three feet away into you, and still going in further into your anus. You cry out in pain at first... muscles cllecnhing inside trying to rid the foregin obect, but relaxing as what you believe to be the nano-bots are being released into the anus. You feel odd for a moment... your friend's penis seems to be going impossibly farther in then it should go. You look down to see your own penis stiffening and you start to wonder if you might be gay. Then, suddenly, you feel another force pushing at the base of your penis. You cry out as you feel your penis being pushed out past it's normal length...5 inches...10 inches... a foot... then all of sudden, you feel your friend's penis burst inside your own penis. The diameter of your penis increasing in size to accomondate your friend's as if it was natural. You can see it literally throbbing and you see the tip of your penis about to tear open from the pressure. You mutter in disbelief a second before it burst open and your friend's penis is now sticking out of the tip of your own like it was nothing. You continue to see his penis growing out of your own until it's five feet longer and it nearly touches the wall facing you before it stops. You then feel yourself being lifted into the air by your friend's giant dick and you start to moan as you look down and see the split skins of your penis curling inwards and pushing the hole that your friend's penis created closer to you. You then feel the sides creating multiple folds and it slowly turns into what you saw in biology books as a vagina. The upper remnants of your penis roll up into a clitoris and all that's left of your masculinity is your physical looks and your scrotum still hanging below.
" Sorry about that." Your friend murmurs to you when he catches you touching your scrotum beneath his penis. " His penis now... you think to yourself. I own the hole from which it's protruding now." You smile as you think this and your friend sighs as he explains medically that the scrotum can't withdraw on it's own biologically once it's been prepared during birth. So it has to be manually pushed in to resume the transformation. He retracts his penis, and you see it slither back into you, then out your rear end and then you hear a slurp as you assume it returned to it's original size without looking back. You feel your friend's arms on your shoulder.
" I've inserted nano-bots into your system to assist in the rest of your transformation with restoring chemicals and such to your DNA. I've also given you the freedom to interact with them vocally while you transform, and you may eject all of anytime you wish when you're done. Just in case you don't want anything unatural running in your system. If you choose to keep them, you can continue to alter your looks whenever you want with them...but you can never be male again." Your friend gives you a brief hug and starts to walk towards the door. " I'll see you tomorrow, I've got a history exam in the morning that I've got to study for. Good-night." He opens the door and shuts it quickly, leaving you to your mid-transformation. " For now on, I'm in control!" You think to yourself happily as you begin to scoop up your scrotum and push it into your newly developed vagina.